Outline View
Table 1 – Muscle Actions on the Spine and Innominates
Muscle Actions on the Spine and Innominates
| Muscle | Lumbo-sacral | Ilium | Origin | Insertion |
| Quadratus Lumborum | CN | CN | Rib 12 & TP L1-4 | Iliac crest |
| Iliacus | – | CN | Iliac fossa | Lesser trochanter |
| Psoas Minor | CN | – | Bodies& discs T12-L1 | Fascia of Psoas Major & Iliacus |
| Psoas Major | CN | – | TP & discs T12-L5 | Lesser trochanter |
| Piriformis | CN | – | S2-4 | Greater trochanter |
| Obturator Externus | – | CN | Obturator | Greater trochanter |
| Longissimus T. pars L. | CN | CN | TP L1-4 | Iliac crest |
| Iliocostalis L. pars L. | CN | CN | TP/AP L1-L5 | Iliac crest |
| Longissimus T. pars T. | N | N | TP/Ribs T1-12 | SP L3-sacrum & iliac crest |
| Iliocostalis L. pars T. | – | N | Ribs 7-12 | Iliac crest |
| Spinalis thoracis | N | – | SP T1-10 | SP T11-12 |
| Lumbosacral multifidus | N | N | Lumbar SP | Lumbar LP, sacrum, Iliac crest |
| Gluteus medius – anterior fibers | – | CN | Outer ilium | Greater trochanter |
| Gluteus minimus –anterior fibers | – | CN | Outer ilium | Greater trochanter |
| Rectus femoris | – | CN | Anterior ilium | Patella & tibia |
| Sartorius | – | CN | Anterior ilium | Tibia |
| Tensor fascia lata – anterior fibers | – | CN | Anterior ilium | Iliotibial band |
| Pectineus | – | CN | Pubic ramus | Femur |
| Adductor Brevis | – | CN | Pubic ramus | Femur |
| Gracilis | – | CN | Pubis | Tibia |
| Adductor Magnus – anterior head | – | CN | Ischial ramus | Femur |
| Internal & External Oblique Muscle Slings | CN on side of IO, N on side of EO |
CN on side of IO, N on side of EO |
See individual muscles below | See individual muscles below |
| Internal oblique | – | CN | Iliac crest, inguinal ligament, & TL fascia | Linea alba, costal cartilage & ribs 8-12 |
| External oblique | – | N | Outer iliac crest | Linea alba, contralateral rectus sheath, & ribs 5-12 |
| Transversus abdominis | N | N | Ribs 6-12, diaphragm, TL fascia, iliac crest, inguinal ligament | Pubic crest, internal oblique aponeurosis |
| Gluteus maximus (iliac part) |
N | – | Outer ilium | Iliotibial band, gluteal tuberosity |
| Gluteus maximus (sacral part) |
CN | – | Sacrum | Iliotibial band, gluteal tuberosity |
| Latissimus dorsi | CN | N | SP T6-L3, Iliac crest | Humerus & contralateral GM |
| GM – Contralateral LD Muscle Sling |
N on GM side CN on LD side |
N on GM side, CN on LD side |
See individual muscles above | See individual muscles below |
| Rectus abdominis | – | N | Xiphoid process | Pubis |
| Semitendinosus | – | N | Ischium | Tibia |
| Semimembranosus | – | N | Ischium | Tibia |
| Biceps femoris (long head) | CN | N | Ischial tuberosity & sacrotuberous ligament | Fibula |
| Adductor magnus – posterior head | – | N | Ischial tuberosity | Femur |
| Pelvic Floor | CN | CN | Innominate & various muscles & fascia | Sacrum & various muscles & fascia |
The table provides the specified muscle or group, action on lumbosacral region and innominate, and origin & insertion.
N=nutation, CN=counternutation, GM = gluteus maximus, LD = latissimus dorsi, IO = internal oblique,
EO = external oblique, T = thoracic/thoracis, L = lumbar/lumborum, TL = thoracolumbar, SP = spinous process,
TP = transverse process, AP = accessory process.